Question: William ate 4 slices of pizza. Omar ate 1 slice. If William ate $\dfrac{4}{7}$ of the pizza, what fraction of the pizza is remaining?
Solution: If 4 slices represent $\dfrac{4}{7}$ of the pizza, there must have been a total of 7 slices. $\text{fraction of pizza remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 5 slices, which leaves 2 out of 7 slices remaining. There is $\dfrac{2}{7}$ of the pizza remaining.